The present disclosure relates to vehicle drive systems. More particularly, the present disclosure relates to a system for and method of optimizing the use of stored energy or power for a hybrid vehicle that is utilized for transit and stationary operation.
Hybrid vehicle drive systems commonly employ at least two prime movers arranged in different configurations relative to a transmission. One known configuration is found in so-called “series-parallel” hybrids. “Series-parallel” hybrids are arranged such that multiple prime movers can power the drive shaft alone or in conjunction with one another.
In a hybrid vehicle drive system, a first and second prime mover (e.g., an internal combustion engine and an electric motor/generator) can be arranged in a parallel configuration and used to provide power to a drive shaft and a power take-off (PTO) shaft through a transmission or to provide power through a transmission or through a shaft and PTO to a transmission. PTO shafts are generally used to drive auxiliary systems, accessories, or other machinery (e.g., pumps, mixers, barrels, winches, blowers, etc.).
Stored power or energy may be used to drive auxiliary systems or other devices when the hybrid vehicle is stationary, such as at a job site. To meet various anti-idle and emission regulations, it may be desirable to power the auxiliary systems and components with stored electrical power instead of with power from an internal combustion engine. The rate at which stored energy is used (varying the power) or stored and the amount of stored energy in a hybrid system can have varying effects on overall vehicle efficiency depending upon how the energy is used during driving. If the vehicle is also a work truck or vehicle, the use of stored energy from a hybrid system can also have differing effects on efficiency at the jobsite, or on overall efficiency if a vehicle is used both in a driving mode and at jobsites. Therefore, there is a need to optimize the use of stored power or energy at job sites and along transportation routes. Because a hybrid vehicle has a finite power storage capacity, there is a need to monitor, predict and control the use of stored electrical power during the transit of the hybrid and during the stationary job needs. Further, there is a need to provide a system for and method of maintaining a sufficient amount of stored power or energy for expected stationary job needs of the hybrid vehicle.